I've never heard of the Kobo, so I dunno how the Simple Touch would compare, but I really enjoy my STR, and I got it when it was still $139. For $99 or $79 from livramax's post, I'd say it's totally worth it.

These cards are fairly easy to make at a fraction of the cost they are sold for. Instructions on how to make them are abound, just google for "nook tablet (or "color") cm7 sd card".

It worth learning to learn to make one's own card -- I have experienced instances where a misbehaving app corrupted the card's content in a way that triggers CM7 into spontaneous reboot during the boot up (thus preventing the Nook from ever completing the CM7 boot up) and the only practical course of action for repair is to burn another image.